A locking member for a fastener, such as a nut or a collar, includes a shank portion and a flanged portion, a bore extending the shank portion and the flanged portion and including a first interior portion located within the shank portion and a containment cavity located within the flanged portion, and an inner wall defining the containment cavity. The containment cavity includes an inner diameter that is greater than an inner diameter of the first interior portion of the bore. The inner wall of the containment cavity includes one or a combination of flat/linear surfaces, concave surfaces, and convex surfaces.